Fix layer count; show layers with no params in detailed log (#19202)

Signed-off-by: Mohammed Yasin <32206511+Y-T-G@users.noreply.github.com>
Co-authored-by: UltralyticsAssistant <web@ultralytics.com>
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

ultralytics/utils/torch_utils.py

@@ -302,15 +302,22 @@ def model_info(model, detailed=False, verbose=True, imgsz=640):
         return
     n_p = get_num_params(model)  # number of parameters
     n_g = get_num_gradients(model)  # number of gradients
-    n_l = len(list(model.modules()))  # number of layers
+    layers = __import__("collections").OrderedDict((n, m) for n, m in model.named_modules() if len(m._modules) == 0)
+    n_l = len(layers)  # number of layers
     if detailed:
-        LOGGER.info(f"{'layer':>5}{'name':>40}{'gradient':>10}{'parameters':>12}{'shape':>20}{'mu':>10}{'sigma':>10}")
-        for i, (name, p) in enumerate(model.named_parameters()):
-            name = name.replace("module_list.", "")
-            LOGGER.info(
-                f"{i:>5g}{name:>40s}{p.requires_grad!r:>10}{p.numel():>12g}{str(list(p.shape)):>20s}"
-                f"{p.mean():>10.3g}{p.std():>10.3g}{str(p.dtype):>15s}"
-            )
+        h = f"{'layer':>5}{'name':>40}{'type':>20}{'gradient':>10}{'parameters':>12}{'shape':>20}{'mu':>10}{'sigma':>10}"
+        LOGGER.info(h)
+        for i, (mn, m) in enumerate(layers.items()):
+            mn = mn.replace("module_list.", "")
+            mt = m.__class__.__name__
+            if len(m._parameters):
+                for pn, p in m.named_parameters():
+                    LOGGER.info(
+                        f"{i:>5g}{mn + '.' + pn:>40}{mt:>20}{p.requires_grad!r:>10}{p.numel():>12g}"
+                        f"{str(list(p.shape)):>20}{p.mean():>10.3g}{p.std():>10.3g}{str(p.dtype).replace('torch.', ''):>15}"
+                    )
+            else:  # layers with no learnable params
+                LOGGER.info(f"{i:>5g}{mn:>40}{mt:>20}{False!r:>10}{0:>12g}{str([]):>20}{'-':>10}{'-':>10}{'-':>15}")
 
     flops = get_flops(model, imgsz)  # imgsz may be int or list, i.e. imgsz=640 or imgsz=[640, 320]
     fused = " (fused)" if getattr(model, "is_fused", lambda: False)() else ""